This study evaluated the charging characteristics of a carbon fiber ionizer for PM2.5 and carried out particle capture laboratory tests after an ionizer was installed upstream of the media of an electret cabin air filter. When the ion concentration per particle (Ni) of the carbon fiber charger was 106ions/cm3, the average charge numbers for each particle were 1.54, 0.88, and 0.49 at 0.6, 1.2, and 1.8m/s of face velocity, respectively (the particle charging times, τ, were 167, 83, and 56ms, respectively). For these face velocities, the PM2.5 removal efficiencies of the filter media were 69.3%, 65.2% and 62.2%, respectively, but increased to 80.4%, 71.2% and 65.5%, respectively, when the ionizer was turned on. The carbon fiber ionizer was then installed in front of an electret cabin filter in the air conditioning system of an automobile, after which field tests were performed at a roadside area. For the same Niτ used in the lab-scale tests, the effects of the carbon fiber ionizer on increasing PM2.5 %Reduction were mild as 9.4%, 4.0%, and 2.8% when the flow rates were at the second, fourth, and sixth levels, respectively (the face velocities were 0.6, 1.2, and 1.8m/s, respectively). The PM2.5 %Reduction can be substantially increased by 20-21%, for a higher value of Niτ (=1.0×108ions s/cm3), which is realized by increasing the power consumption of the carbon fiber ionizer.
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Mechanical Engineering
- Fluid Flow and Transfer Processes
- Atmospheric Science